1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer.
2. Description of the Related Art
Digital pens are capable of digitizing what is written in ink on a piece of paper, and capable of allowing such a hand written information on a display unit. One such digital pen is the Anoto pen capable of recognizing the Anoto pattern. The Anoto pattern is a dot pattern that contains dots formed near the intersections of grid lines. The grids are spaced apart by about 0.3 mm. As the Anoto pen moves on the piece of the dot pattern, the positions of the pen tip are identified.
In order for a digital pen to identify the location of its pen tip on a sheet of paper, the dots must be printed on the sheet of paper very accurately. However, some image forming apparatuses are unable to print the dots with high accuracy. In other words, a dot pattern for use with the digital pen is difficult to accurately form.